Gaseous current separator



Nov. 5, 1963 w. SAUERMANN 3,109,807

GASEOUS CURRENT SEPARATOR Filed NOV. 23, 1960 FIG.

,cya 2 FIG. 4'

INV EN TOR.

bJ-bvm SW W BY United States Patent Of many Filed Nov. 23, 1960, Ser.No. 71,286 Claims priority, application Germany Nov. 27, 1959 8 Claims.(Cl. 209-136) The present invention relates to grain classifyingstructure of the gaseous current type.

Thus, there are certain industries where graular material is collectedwithout any consideration being given to the size of the particles ofthe granular material, and for further processing it is necessary toseparate the granular material into classes of different size ranges,respecively.

It is the object of the present invention to provide an apparatus whichwill efficiently separate such granular material into classes of varioussize ranges.

Another object of the present invention is to provide an apparatus ofthe above type which will classify the granular material according toits size in a manner which is not influenced to any substantial degreeby the particular configuration of the particles of the material.

A further object of the present invention is to provide a structure ofthe above type which is inexpensive and at the same time capable ofoperating reliably with a minimum of maintenance.

With the above objects in view the invention includes in a grainclassifying apparatus which is capable of classifying granular materialinto various size ranges, an elongated tubular gas guide having oppositeopen ends, closed side walls, and top and bottom walls. The top Wall ofthe gas guide is formed with at least one opening and the bottom Wall ofthe gas guide is formed with a plurality of openings passing throughthis bottom wall and distributed longitudinally therealong. A supportmeans supports the gas guide of the invention with one of its open endsat an elevation higher than the other of its open ends and the granularmaterial which is to be classified is dropped onto the top wall so as tomove downwardly therealong to the opening of the top wall and so as tofall through this opening into the gas guide to fall toward the bottomwall thereof. When a stream of gas flows upwardly along the interior ofthe gas guide from its other toward its one end. This stream of gas willengage the granular material falling from the opening of the top walltoward the bottom wall and will distribute this material along thebottom wall with the material of smallest grain size located nearest tothe upper end of the bottom wall and the granular material being ofgradually larger grain size toward the lower end of the bottom wall, sothat granular material of various size ranges will respectively dropthrough the openings of the bottom wall.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

FIG. 1 is a partly schematic, sectional, side elevation of an apparatusaccording to the present invention;

FIG. 2 is a longitudinal sectional fragmentary view on a large scale ofa partition of the invention: showing in particular one of the openingspassing therethrough;

FIG. 3 is a fragmentary longitudinal sectional elevation of part of thetop wall of the gas guide of the invention showing one possibleembodiment of a closure means cooperating with an opening of this topwall; and

3,169,807 Patented Nov. 5., 1963 FIG. 4 is a transverse sectional viewof the structure of FIG. 1 taken along line 4-4 of FIG. 1 in thedirection of the arrows.

Referring now to FIG. 1 it will be seen that the entire structure iscarried by a support means which includes a suitable framework 14. Asmay be seen from FIG. 1 the framework supports in the manner describedbelow an elongated. tubular gas guide which includes the top wall 3, thebottom wall 10, and the opposite side walls 3a and 3b (FIG..4). Theelongated gas guide has opposite open ends, and the support means 1214supports the gas guide in an inclined position with one of its open endsat a higher elevation than the other of its open ends. Thus, theframework 14 and the gas guide itself carry suitable brackets 13 towhich rods 12 are pivotally linked as shown in FIG. 1, and these rods 12not only support the gas guide but permit the same to be vibratedlongitudinally. A vibrating means 1, diagrammatically shown in FIG. 1,is operatively connected with the gas guide to longitudinally vibratethe same, this vibrating means 1 having any suitable form such as, forexample, that of a motor carrying an eccentrically positioned Weightwhich will produce the vibrations upon operation of the motor. Thebrackets 13 which are fixed to the gas guide may be located at oppositesides thereof, and there may be four rods 12 two at each side of the gasguide respectively pivotallyconnected both with the framework 14 as wellas with the gas guide to support the latter for swinging forward andrearward movement in response to the vibrations derived from thevibrating means 1.

The side walls 3a and 3b of the gas guide are closed, while the top Wall3 and the bottom wall 10 are formed with openings, and these openingsextend completely across the top and bottom walls. Thus, it will be seenthat the top wall 3 is formed with a plurality of openings 4 distributedalong the top wall 3 and passing through the latter, each of theseopenings 4 extending completely across the top wall 3 between the sidewalls 3a and 3b. A closure means 5 cooperates with each of the openings4 to optionally close or open the latter according to the will of theoperator. As is indicated in FIG. 3, this closure means may take theform of a hinge fastened by suitable screws to the wall 3 and having aswingable cover member 5a which is turnable from the closed positionindicated in FIG. 3 in a counterclockwise direct-ion, as indicated bythe arrow of FIG. 3 to an open position. With this arrangement aselected one of the openings 4 can be uncovered while the remainingopenings remain closed, and thus the operator can select the point alongthe wall 3 through which the granular material is to be dropped into theinterior of the gas guide.

A supply means is provided for supplying granular material to beclassified, and this supply means is in the form of a stationary hopper2 carried by the framework 14 and having a lower discharge end locatedclosely adjacent to the .top wall 3. It will be noted that the dischargeend of the hopper has a width equal to the width of the top wall 3 sothat the granular material is uniformly distributed across the top wall3 to move downwardly along the latter to the selected opening 4 whichhas been opened by the operator and to drop through this opening 4 intothe interior of the gas guide of the invention.

With this construction if a stream of a gas such as air moves upwardlyalong the interior of the gas guide the granular material fallingthrough the selected opening 4 will be distributed longitudinally alongthe interior of the gas guide and will thus be distributed along thebottom Wall 10.- The distribution of the granular material along thebottom wall 10 will necessarily be according to grain size. Thus,extremely small and therefore extremely light particles will besuspended in the stream of gas and will simply be carried out of the gasguide through the upper 3 end thereof. At the upper end of the bottomwall will be located relatively small particles while the largestparticles will be located at the bottom end of the gas guide and willfall out of the bottom end thereof, and'in between these extremes thegranular material will be arranged with the size of the particlesgradually increasing from the upper toward the lower end of the gasguide.

The bottom wall 10 is formed with a series of openings also extendingcompletely across the bottom wall 10 as well as through the latter anddistributed longitudinally thereon, and these openings respectivelycommunicate with the relatively short tubular outlets 1.1, 11", and 11"shown in FIG. 1, these outlets directing material into chutes,respectively, which causes the material to be conveyed to desiredlocations. As is apparent from FIG. 1, the smallest range of sizes willdrop through the outlet 11', the intermediate range of sizes will dropthrough the outlet 11, and the largest range of sizes will drop throughthe outlet 11''. Of course, there will be a still larger range of sizeswhich will simply fall through the lower open end of the gas guide,while a range of sizes even smaller than that which falls through theoutlet 11' will be carried oil with the stream of air or other suitablegas.

In practice, grain classifiers of the above type are never 100%efiicient'. That is, in actual practice it never happens'that onlygrains of a particular range of sizes are classified into one group.There is always to some extent some granular material of the next lowerand next higher size ranges located in each particular range of sizesalthough of course the major part of the granular material of each sizerange conforms to the range of sizes of the particular size range. Thus,it will be found that with the structure of the invention as describedabove although the granular material dropping, for example, through theoutlet 11" will for the most part have a range of sizes intermediate thesize range of the granular material ialling through the outlets 11 and11", nevertheless some of the material falling through the outlet '11"will be of the same size range as the material ialling through theoutlet 11' and some will also be in the same size range as the materialfalling through the outlet 11". One of the principal reasons for thisundesirable result resides in the fact that eddy current and turbulencein the stream of gas prevents the distribution of the granular materialalong the bottom wall with the uniformity which is desired.

According to a further feature of the invention, the structure of thegas guide of the invention is such that laminar gas flow is maintainedso as to provide an exceedingly efficient uniformity of distribution ofthe material along the bottom wall 10 and thus the extent to whichgranular material in any one size range 'will have the size of the nextlower and next higher size ranges will be very greatly reduced certainlyfar beyond what has been experienced in known apparatus up to thepresent time. Thus, with the structure of the invention there arearranged within the gas guide a plurality of partitions 6 located oneabove the other and spaced from each other as well as from the top andbottom walls 3 and 10, and these partitions 6 are carried by the sidewalls 3a and 3b, as indicated in FIG. 4. The partitions 6 are parallelto each other, as well as to thetop and bottom walls 3 and 10', as isapparent from FIG. 1. Each of the partitions 6 is formed with aplurality of openings 7 passingtherethrough and distributed therealong,andeach' opening 7 extends completely across the partition, as isapparent from FIG. 4. As is most clearly shown in FIG. 2, each opening 7is inclined oppositely to the inclination of the gas guide. It will benoted that the openings 7 are uniformly distributed along eachpartition.

,At the upper open end of the gas guide there is a conduit means 9 whichcommunicates with this open end of the gas guide to convey the gas awayfrom the latter, and a portion of the conduit means 9 is provided with afan the gas guide of the invention.

or blower 16 which creates the stream of gas flowing upwardly into thegas guide through the open lower end thereof as indicated at a inFIG. 1. To the upper ends of the partitions 6, at the upper open end ofthe gas guide, are fixed a plurality of guide vanes 8 which are parallelto each other and extend into the conduit 9 in the manner indicated inFIG. 1, so that these vanes 8 maintain the laminar flow in the gas,which may be air, flowing into the conduit 9. As was pointed out above,the finest smallest particles will simply be suspended in the stream ofgas and will be carried along with the stream of gas through thedischarge conduit 9, and this conduit may lead to a conventionalseparator in which the dust-like particles are separated from the gasstream;

As may be seen from FIG. 1, all of the relatively fine small granularparticles which flow along the path indicated by the dotted line c oralong a more horizontal path will be carried off with the stream of gasthrough the conduit means 9 to the separator. The stream of gas flowingfrom the region a up to the upper open end of the gas guide at theregion b, will provide one range of sizes of the granular materialbetween the paths indicated by the dotted lines c and d.v As is apparentfrom the line d the material is advanced upwardly along the severalpartitions and drops down through the next lower opening 7 to be movedagain upwardly in between the next pair of lower partitions, etc., andthus there will be a particular size range which will fall through theoutlet 11'. In the same way a second range of sizes will be locatedbetween the paths d and e shown in dotted lines in FIG. 1, and theparticles in this range of sizes will fall through the outlet 11", whilethe next larger range of sizes will in a very similar way fall throughthe outlet 1", and of course particles of even larger size will drop outof the lower open end of the gas guide as indicated at f.

The various size ranges can be regulated by selecting the opening 4through which the material is to drop into The inclination of theopenings 7 permit these openings to extend generally in the direction ofthe gas stream so that there is a minimum change in the direction ofmovement of the granular material as it moves through the openings 7.

The arrangement of the several partitions 6 with their openings 7 notonly maintains the gas flow laminar, in addition the dropping of thegranular material toward the bottom wall 10 is repeatedly interruptedand the material repeatedly falls through the openings 7 to berepeatedly subjected to the several layers of the gas stream, so that inthis way irrespective of the shape of the particles, that is to say,irrespective of whether the particles are circular, cubicle, orsomewhere in between these extremes, they will nevertheless be groupedaccording to the size ranges and the configuration of the particlesthemselves will not have any influence on their classification so thatthe location in any one size range of particles from the next higher ornext lower size range resulting from the particular configuration of theparticles is also greatly diminished with the structure of theinvention. Furthermore, the provision of the partitions with theopenings 7 divides the stream of granular material falling through theselected opening 4 into several substreams of diiferent size rangesbefore the granular material reaches the bottom wall 10, so that in thisway also the efficiency of the classification is enhanced.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofgrain classifying structures differing from the types described above.

While the invention has been illustrated and described as embodied invibratory grainclassifying structures, it is not intended to be limitedto the details shown, since various modifications and structural changesmay be made without departing in any way from the spirit of the present1 reveal the gist of the present invention that others can by applyingcurrent knowledge readily adapt it for various applications withoutomitting features that, from the standpoint of prior art, fairlyconstitute essential charactenistics of the generic of specific aspectsof this invention and, therefore, such adaptations should and areintended to be comprehended within the meaning and range of equivalenceof the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In an apparatus for classifying granular material into classes ofdifferent size ranges, in combination, an elongated tubular gas guidehaving opposite open ends, closed side walls, and top and bottom walls,said top wall being formed with a plurality of openings at predeterminedpoints along said top wall through which granular material to beclassified drops into the tubular gas guide and said bottom wall beingformed with a plurality of openings distributed along said bottom walland passing therethrough; a plurality of conduit means communicatingrespectively with said openings in said bottom wall for receivingrespectively thereto granular material of different sizes; means forcreating a gas flow within said elongated tubular gas guide in directionfrom one of its open ends to the other of its open ends; support meanssupporting said tubular gas guide in an inclined position with said oneof its open ends located at the lower elevation than said other of itsopen ends; and supply means located above the said top wall of said gasguide adjacent said other end thereof for supplying through at least oneof the openings in said top wall into the tubular gas guide granularmaterial to be classified, so that when a gas flows up through said gasguide from said one toward said other open end thereof the granularmaterial dropping through said opening of said top wall will bedistributed by the gas along said bottom wall to fall according topredetermined size ranges through said openings of said bottom wall,respectively.

2. In an apparatus for classifying granular material into classes ofdifferent size ranges, in combination, an elongated tubular gas guidehaving opposite open ends, closed side walls, and top and bottom walls,said top wall being formed with a plurality of openings at predeterminedpoints along said top wall through which granular material to beclassified drops into the tubular gas guide and said bottom wall beingformed with a plurality of openings distributed along said bottom walland passing therethrough; a plurality of conduit means communicatingrespectively with said openings in said bottom wall for receivingrespectively thereto granular material of different sizes; means forcreating a gas flow within said elongated tubular gas guide in directionfrom one of its open ends to the other of its open ends; support meanssupporting said tubular gas guide in an inclined position with said oneof its open ends located at a lower elevation than said other of itsopen ends; and supply means located above said top wall of said gasguide adjacent said other end thereof for supplying to at least one ofthe openings in said top wall into the tubular gas guide granularmaterial to be classified, so that when a gas flows up through said gasguide from said one to ward said other open end thereof the granularmaterial dropping through said opening of said top Wall will bedistributed by the gas along said bottom wall to fall according topredetermined size ranges through said openings of said bottom Wallrespectively; and vibrating means operatively connected to said gasguide for longitudinally vibrating the same.

3. In an apparatus for classifying granular material into classes ofdifferent size ranges, in combination, an elongated tubular gas guidehaving opposite open ends, closed side walls, and top and bottom walls,said top wall being formed with at least one opening through whichgranular material to be classified drops into the tubular gas guide andsaid bottom wall being formed with a plurality of openings distributedalong said bottom wall and passing therethrough; a plurality of conduitmeans communicating respectively with said openings in said bottom wallfor receiving respectively thereto granular material of different sizes;means for creating a gas flow within said elongated tubular gas guide indirection from one of its open ends to the other of its open ends;support means supporting said tubular gas guide in an inclined positionwith said one of its open ends located at a lower elevation than saidother of its open ends so that when a gas flows through said gas guidefrom said one toward said other open end thereof the granular materialdropping through said opening of said top wall will be distributed bythe gas along said bottom wall to fall according to predetermined sizeranges through said openings of said bottom wall, respectively; and aplurality of partitions arranged one above the other between said topand bottom walls and spaced from each other as well as from said top andbottom walls, said partitions being carried by said side walls and eachpartition being formed with a plurality of openings passing therethroughand distributed therealong so that the granular material falling throughsaid opening of said top wall will fall through the openings of saidpartitions to reach said bottom wall, said partitions maintaining theflow of gas upwardly through said gas guide laminar.

4. In an apparatus for classifying granular material into classes ofdifferent size ranges, in combination, an elongated tubular gas guidehaving opposite open ends, closed side walls, and top and bottom Walls,said top wall being formed with at least one opening through whichgranular material to be classified drops into the tubular gas guide andsaid bottom wall being formed with a plurality of openings distributedalong said bottom wall and passing therethrough; a plurality of conduitmeans communicating respectively with said openings in said bottom wallfor receiving respectively thereto granular material of different sizes;means for creating a gas flow within said elongated tubular gas guide indirection from one of its open ends to the other of its open ends;support means supporting said tubular gas guide in an inclined positionwith said one of its open ends located at a lower elevation than saidother of its open ends so that when a gas flows through said gas guidefrom one said toward said other open end thereof the granular materialdropping through said opening of said top wall will be distributed bythe gas along said bottom wall to fall according to predetermined sizeranges through said openings of said bottom wall, respectively; and aplurality of partitions arranged one above the other between said topand bottom walls and spaced from each other as well as from said top andbottom walls, said partitions being carried by said side walls and eachpartition being formed with a plurality of openings passing therethroughand distributed therealong so that the granular material falling throughsaid opening of said top Wall will fall through the openings of saidpartions to reach said bottom wall, said partitions maintaining the flowof gas upwardly through said gas guide laminar, each of said openings ofsaid partitions extending transversely between said side walls and beinginclined oppositely to the inclination of said gas guide.

5. In an apparatus for classifying granular material into classes ofdifferent size ranges, in combination, an elongated tubular gas guidehaving opposite open ends, closed side walls, and top and bottom walls,said top wall being formed with at least one opening through whichgranular material to be classified drops into the tubular gas guide andsaid bottom wall being formed with a plurality of openings distributedalong said bottom wall and passing therethrough and through whichgranular material of different size ranges is adapted to fall,respectively; means for creating a gas flow within said elongatedtubular gas guide in direction from one of its open ends to the other ofits open ends; support means supporting said tubular gas guide in aninclined position with said one of its open amass? ends located at alower elevation than said other of its open ends so that when :a gasflows through said gas guide from said one toward said other open endthereof the granular material dropping through said opening of said topwall will be distributed by the gas along said bottom wall to fallaccording to predetermined size ranges through said openings of saidbottom wall, respectively; a plurality of partitions arranged one abovethe other between said top and bottom walls and spaced from each otheras well as from said top and bottom walls, said partitions being carriedby said side walls and each partition being formed with a plurality ofopenings passing therethrough and distributed therealong so that thegranular material falling through said opening of said top wall willfall through the openings of said partitions to reach said bottom wall,said partitions maintaining the flow of gas upwardly through said gasguide laminar; conduit means communicating with said one endof said gasguide for conveying gas away from the latter; and a plurality of guidevanes respectively fixed to the upper ends of said partitions at saidone end of said gas guide and extending into said conduit means formaintaining laminar flow therein.

6. In an apparatus for classifying granular material into classes havingpredetermined size ranges, in combination, an elongated tubular gasguide having opposite open ends, closed side walls, and top and bottomwalls, said top wall being formed with a plurality of openings passingtherethrough and distributed therealong and said bottom wall also beingformed with a plurality of openings passing therethrough and distributedtherealong; a plurality of closure means respectively cooperating withsaid openings of said top wall for selectively closing all except aselected one of said openings of said top wall; means for creating a gasflow within said elongated tubular gas guide in direction from one ofits open ends to the other of its open ends; support means supportingsaid gas guide in an inclined position where one of said open endsthereof is at a lower elevation than said other of said open endsthereof; and supply means located over said top wall of said gas guideadjacent said other end thereof for supplying to the upper surface ofsaid top wall granulated material to be classified, whereby the granularmaterial will move by gravity downwardly along said top wall until thegranular material reaches the selected top wall opening which is openand falls therethrough into said gas guide, whereby when a stream of gasflows upwardly along the interior of said guide from said one towardsaid other open end thereof, the gas will distribute the granularmaterial along said bottom Wall according to various size ranges whichwill respectively fall through said openings of said bottom vwall.

' closure means respectively cooperating with said openings of said topwall for selectively closing all except a selected one of said openingsof said top wall; means for creating a gas fiow within said elongatedtubular gas-guide in direction from one of its open ends to the other ofits open ends; support means supporting said gas guide in an inclinedposition where one of said open ends thereof is at a lower elevationthan said other of said open ends thereof; supply means located oversaid top wall of said gas guide adjacent said other end thereof forsupplying to the upper surface of said top wall granulated material tobe clasified, whereby the granular material will move by gravitydownwardly along said top wall until the granular material reaches theselected top wall opening which is open and falls therethrough into saidgas guide, whereby when a stream of gas flows upwardly along theinterior of said guide from said one toward said other open end guidebetween said top and bottom walls thereof, saidpartitions being carriedby said side walls and each partition being formed with a plurality ofopenings passing therethrough and distributed therealong so that thegranulai material which drops through the selected opening of said topwall will fall through said openings of said partitions before reachingsaid bottom wall, each of said openings of said partitions extendingtransversely between said side walls of said gas guide and beinginclined oppo sitely to said gas guide; conduit means communicating withsaid one 'end of said gas guide for conveying gas from the latter; aplurality of guide vanes respectively .fixed to the ends of saidpartitions at said one end of said gas guide and extending into saidconduit means, said parations maintaining a laminar gas flow in said gasguide and said vanes maintaining the laminar gas fiow'into said gasguide and said vanes maintaining the laminar gas flow into said conduitmeans; and vibrating means cooperating with said gas guide forlongitudinally vibrating the latter.

8. In an apparatus for classifying granular material into classes havingpredetermined size ranges, in combination, an elongatedtubular gas guidehaving opposite open ends, closed side walls, and top and bottom walls,said top wall being formed with a plurality of openings passingtherethrough and distributed therealong and said bottom wall also beingformed with a plurality of openings passing therethrough and distributedtherealong; a plurality of closure means respectively cooperating withsaid openings of said top wall for selectively closing all except aselected one of said openings of said top wall; support means supportingsaid gas guide in an inclined position where one of said open endsthereof is at a lower elevation than the other of said open endsthereof; supply means located over said top wall of said gas guideadjacent said other end thereof for supplying to the upper surface ofsaid top wall granulated material to be classified, whereby the granularmaterial will move by gravity downwardly along said top wall until thegranular material reaches the selected top wall opening which is openand falls therethrough into said gas guide, whereby when a stream of gasflows upwardly along the interior of said guide from said one towardsaid other open end thereof,the gas will distribute the granularmaterial along said bottom wall according to Various size ranges whichwill respectively fall through said openings of said bottom wall; aplurality of partitions located one above the other, spaced from eachother as Well as from said top and bottom walls, and extending along theinterior of said gas guide between said top and bottom walls thereof,each partition being formed with .a plurality of openings passingtherethrough and distn'buted therealong so that the granular materialwhich drops through the selected opening of said top wall will fallthrough said openings of said partitions before reaching said bottomwall; and means cooperating with said gas guide for creating therein astream of gas flowing longitudinally through said gas guide from saidone toward said other open end thereof in opposition to the direction inwhich the granular material tends to move by gravity along saidpartitions and bottom wall.

References Cited in the file of this patent UNITED STATES PATENTS 14,865Goodrich May 13, 1856 340,542 Bates Apr. 27, 1886 730,229 Burr June 9,1903 1,230,600, Wegner' Oct. 1, 1918 FOREIGN PATENTS 445,709 GreatBritain Apr. 16, 1936 828,125 France May 11, 1 938

1. IN AN APPARATUS FOR CLASSIFYING GRANULAR MATERIAL INTO CLASSES OFDIFFERENT SIZE RANGES, IN COMBINATION, AN ELONGATED TUBULAR GAS GUIDEHAVING OPPOSITE OPEN ENDS, CLOSED SIDE WALLS, AND TOP AND BOTTOM WALLS,SAID TOP WALL BEING FORMED WITH A PLURALITY OF OPENINGS AT PREDETERMINEDPOINTS ALONG SAID TOP WALL THROUGH WHICH GRANULAR MATERIAL TO BECLASSIFIED DROPS INTO THE TUBULAR GAS GUIDE AND SAID BOTTOM WALL BEINGFORMED WITH A PLURALITY OF OPENINGS DISTRIBUTED ALONG SAID BOTTOM WALLAND PASSING THERETHROUGH; A PLURALITY OF CONDUIT MEANS COMMUNICATINGRESPECTIVELY WITH SAID OPENINGS IN SAID BOTTOM WALL FOR RECEIVINGRESPECTIVELY THERETO GRANULAR MATERIAL OF DIFFERENT SIZES; MEANS FORCREATING A GAS FLOW WITHIN SAID ELONGATED TUBULAR GAS GUIDE IN DIRECTIONFROM ONE OF ITS OPEN ENDS TO THE OTHER OF ITS OPEN ENDS; SUPPORT MEANSSUPPORTING SAID TUBULAR GAS GUIDE IN AN INCLINED POSITION WITH SAID ONEOF ITS OPEN ENDS LOCATED AT THE LOWER ELEVATION THAN SAID OTHER OF ITSOPEN ENDS; AND SUPPLY MEANS LOCATED ABOVE THE SAID TOP WALL OF SAID GASGUIDE ADJACENT SAID OTHER END THEREOF FOR SUPPLYING THROUGH AT LEAST ONEOF THE OPENINGS IN SAID TOP WALL INTO THE TUBULAR GAS GUIDE GRANULARMATERIAL TO BE CLASSIFIED, SO THAT WHEN A GAS FLOWS UP THROUGH SAID GASGUIDE FROM SAID ONE TOWARD SAID OTHER OPEN END THEREOF THE GRANULARMATERIAL DROPPING THROUGH SAID OPENING OF SAID TOP WALL WILL BEDISTRIBUTED BY THE GAS ALONG SAID BOTTOM WALL TO FALL ACCORDING TOPREDETERMINED SIZE RANGES THROUGH SAID OPENINGS OF SAID BOTTOM WALL,RESPECTIVELY.